Hydraulic rotary system of drilling with reverse water circulation



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HYDRAULIC ROTARY SYSTEM OF DRILLING WITH REVERSE WATER CIRCULATION Filed Sept. 12, 1952 2 Sheets-Sheet 1 INVEN R )R S :tl'lu.

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Aug. 9. 1955 VENEZIANI ET AL 2,715,016

HYDRAULIC ROTARY SYSTEM OF DRILLING WITH REVERSE WATER CIRCULATION Filed Sept. 12, 1952 2 Sheets-Sheet 2 Wis s c u/v(\ \}EQI 1 I o E H i H T F I Y V l N J -v y g r 5 E] g Y I! T F A United States Patent HYDRAULIC ROTARY SYSTEM OF DRI LLING WITH REVERSE WATER CIRCULATION This invention relates to hydraulic rotary drilling of the soil of the kind in which the drilling fluid is flowed down the drilled hole and is sucked through the drill pipe. As this circulation takes place in reverse direction with regard to the usual hydraulic rotary drilling system it shall be termed hereinafter with reverse circulation.

In the usual processes of hydraulic rotary drilling with sucked reverse circulation, the drill pipe terminates with a syphon-like pipe, the vertical part of which is connected, through the rotary swivel and with a watertight seal, to the drill pipe, whilst the other branch is connected to the fixed discharging line through which the drilling fluid, charged with cuttings, is flowed into a setting pit.

In order to obtain this, a vacuum pump is connected to the syphon top where it keeps sufficient vacuum to maintain the circulation while a sand pump is assembled at the end of the discharging line in order to suck and discharge the drilling fluid charged with cuttings.

Very eflicient pumps are required with this method of procedure, and it is necessary that they generate a powerful suction in order to work with fluids charged with cuttings, which generally are detrimental to the operation of the pumps.

According to the invention, the inconveniences of the previous devices are overcome, by fitting in the syphon top an ejector which helps in effecting a suction in the drill pipe, and in ejecting the drilling fluid together with the cuttings through the discharging branch of the syphon.

According to the invention, the ejector (or jet pump), can work jointly with a vacuum pump, which is also fitted in the syphon top, in which case the function of the ejector is substantially that of ejecting the drilling fluid charged with cuttings.

The invention will be better understood from the following specification, reterred to the attached drawings, in which:

Figure l is a sketch, with some parts omitted, of a hydraulic rotary rig, with the improved reverse ejection of the drilling fluids charged with cuttings, according to the invention, and

Figures 2 and 3 show in detail two sections of the arrangement of an ejector in the top of the syphon.

Referring to Fig. l, D is a drilling bit screwed to a drill pipe string L, at the upper end of which is the usual grief stem M, which passes through the bushings in the rotary table R, driven by an engine or motor through the bevel gear B. This grief stem M is connected with the rotary swivel which is suspended to the hook of a travelling block P mounted on a tall derrick K.

Inside the grief stem is assembled, free to turn by means of the usual water-tight seals, the ascending branch A of an elbow pipe having an inclined descending branch S. At the top of the elbow pipe is fitted an ejector E, connected to a source of fluid under pressure or to a pump Z, whereby the nozzle I of the ejector projects the 2 fluid, fed to it under pressure, in the direction of the discharging branch S. e

In order to complete the action of the ejector E and to prime same at the beginning of the operation, a pipe V connected (through a vacuum tank) to the suction side of a vacuum pump W, is fitted near the ejector nozzle J.

In the section shown in Figs. 1 and 2 the elbow tube AS is maintained at a fixed height by a collar carried by hinged arms C attached to the derrick K. The ascending tube branch A can slide inside the lowering grief stem M and a tight fit between the same is ensured by packing rings Y, Y. The grief stem M can be lowered only by lowering pulley P.

In the modification of the device, shown in section in Fig. 3 the elbow tube AS can only rotate inside the grief stern M, while being raised and lowered with it.

The operation is as follows:

When a hole has to be drilled, the rotary table R is turned so as to turn grief stem M with attached drill pipes string L and the usual apertured drilling bit D, while at the same time drilling fluid flows through an overflow pipe G from a pit X, into the hole. This fluid is sucked through the drill bit and drill pipe string L, grief stern M and elbow pipe AS, by the ejector E mounted at the top of the ascending branch A of the elbow tube, and is ejected, through the discharging branch S, into the pit X. After the setting of cuttings, the fluid may be flowed again into the hole through overflow pipe G.

As the drilling proceeds, the grief stem is lowered down through the driving bushings of rotary table R, while the elbow pipe AS can either be standing at a fixed height (Fig. 2) or be lowered with it (Fig. 3). In the first case each time a throttled part M" of the grief stern M abuts against a lower packing Y between the stem M and the ascending branch pipe A, the grief stem M is raised again to the position as shown and a new drill pipe section is inserted between the drill pipe string already in the hole and the lower end of the grief stern M. In both cases the water flows freely into the drilled hole and is sucked through the pipe string and the grief stem M and is let out through the elbow pipe AS.

Of course, the invention may undergo a number of variations within the scope of the appended claim, while conserving the characteristic of the reversed water circulation, viz. that the water is allowed to flow down outside of the pipe string and is sucked through the same pipes together with the drill cuttings.

Of course the invention may undergo a number of variations within the scope of the appended claim:

We claim:

A drilling apparatus comprising a derrick, a traveling block suspended from said derrick, a rotary table on said derrick, means for driving said table, a grief stem suspended from said block and slidably mounted on said table to rotate therewith, a drill pipe string carried by and connected with said grief stern, an apertured drill bit on the lower end of said drill pipe string, a non-rotatable vertical suction branch slidably mounted within the upper part of said rotary grief stem, means connected with said suction branch beyond said grief stern and secured to said derrick and supporting said suction branch independently of said grief stem, packing means forming a fluid-tight seal between said relatively rotatable and slidable grief stem and suction branch, a descending outlet branch connected by an elbow to the upper end of said suction branch and discharging into a pit, the top of said outlet branch having a connection to the suction side of a vacuum pump, a jet nozzle opening into said elbow and directed toward said outlet branch, means connected With said jet nozzle for supplying fluid under pressure 4 through said nozzle and into said outlet branch to genstring, grief stem and suction branch and is ejected erate a suction in said grief stem and drill pipe string, through said outlet branch back into the pit. and an overflow pipe in communication with the pit into which the outlet branch discharges and opening into Referencss Cited in the file of this Patent the drill hole drilled by said bit, whereby the water freely 5 UNITED STATES PATENTS flowing from the pit into the drilled hole is sucked, to- 199 640 Haas et a1 Jan 29 1878 gether with the dr1ll cuttlngs, through the b1t, drill pipe 2,127,728 Grant Aug 23 1938 

